Which scientist is known for her work on radioactivity and the discovery of radium and polonium?
A. Marie Curie
B. Lise Meitner
C. Dorothy Hodgkin
D. Rosalind Franklin
Answer: Option A
Solution (By JKExamLibrary)
Marie Curie, along with her husband Pierre, conducted pioneering research on radioactivity (a term she coined). In 1898, they discovered two new radioactive elements: polonium (named after her native Poland) and radium. She was the first woman to win a Nobel Prize and the only person to win in two different scientific fields (Physics and Chemistry).
Explanation:
Sodium bicarbonate (NaHCO₃) neutralizes excess stomach acid (HCl) and provides relief from acidity. It is a mild base. NaOH is too strong and corrosive. NaCl is table salt; CaSO₄ is used in plaster of Paris.
Explanation:
Ant sting contains formic acid (methanoic acid, HCOOH). It causes a burning sensation. It can be neutralized by applying a mild base like baking soda. Acetic acid is in vinegar, citric acid in lemons, lactic acid in curd.
Explanation:
Ozonation is a powerful disinfection method that kills bacteria and viruses faster than chlorine. Unlike chlorine, ozone decomposes back into oxygen and does not leave a residual taste or form harmful chlorinated organic byproducts (like trihalomethanes), making it safer for drinking water.
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